Caolionn O'Connell

Bomb Busters for Science

The best abstract ever:

We discuss the possibility of utilizing the ultra-high energy neutrino beam (~ 1000 TeV) to detect and destroy the nuclear bombs wherever they are and whoever possess them.

I think as far as all possible abstract techniques, this is the way one should go. Grab your audience immediately, include something vaguely technical (TeV) and mention nuclear bombs so you can get lots and lots of defense money. You might think this abstract is a lot of hooey, and you really wouldn't be wrong, but it originates from a real paper published in 2003, titled Destruction of Nuclear Bombs Using Ultra-High Energy Neutrino Beam.

My favorite line: "We believe the only way this machine may be built when all the countries on earth agree ... by creating an organization which may be called the 'World Government' for which this device becomes the means of enforcement." Brilliant, simply brilliant! What is actually interesting in this paper is the recommended first step in researching this technology, which may take "an order of a century to achieve."

(1) First, we should construct a neutrino factory which could have substantially lower energy than even 1 TeV. The purpose is to fully understand the properties of the neutrino including mass, mixing angles, CP violating phase, Majorana property and the interactions with other particles.

Translation: We will promise the moon, if you just let is do some interesting basic physics.

This paper was mentioned over lunch as an example of the extremes scientists will go to for funding. I thought it was a joke, but after reading the paper, it seems they wrote it in earnest. Is this what we have been reduced to? Must we whore ourselves for defense money in order to get funding for basic science research? Granted neutrino projects have become "popular" and seem to have secure funding for the time being, but perhaps they could pull the "nuclear-bomb-sniffer" card when things get a little iffy. We need to start thinking outside the research box into more military-based scientific applications. It would certainly be more lucrative than a bake sale.

Really Tall

My nephew, Dominic, is 3 years old. He turns 4 in August. He is at an age where he is a sponge for all information, but he gets a little bored when I accurately answer his bizarre questions. So instead of giving the correct explanation for the origins thunder, I have started to make sh*t up. He's not my kid, so any long-term scarring from my imaginative answers will be blamed on his parents. Not to mention, he's much more entertained about giants running into each other than the difference in speed between light and sound.

When Sam (known as "Uncle Sam") and I were in L.A. last, Dominic was curious about why Uncle Sam was so tall. Sam is 6'3" and, well, Dominic is 3 - so Sam looks REALLY tall. We told him that Uncle Sam hangs upside down like a bat every night and that this stretches him to be taller. Dominic loved this and his eyes got all big in wonder, "Really?!" Apparently, this left an imprint on my nephew. My sister called me after their last parent-teacher conference and said Dominic made a picture of Uncle Sam. I was worried that he told his teacher about Sam being a bat at night, but Dominic seems to be more mesmerized with him being tall rather than a bat. She sent me the picture and thankfully Uncle Sam was labeled, cause I'm afraid his neo-modernist crayon drawing was a mystery to me. My sister says the really straight line is quite the accomplishment for him. When you are only 3, such things are an accomplishment. I'm jealous.

D'oh!

Apparently, I am the only person who doesn't know this, but it seems when you sign up for a paper at a conference you implicitly sign up for a poster as well. How did I miss this? How does everyone else seem to know this but neglect to mention it to me? Crap! To add insult to injury, the paper is due BEFORE the conference. If physicists are known for anything, it is the desire to sleep in and severe procrastination. This is a well-known fact. With that in mind, why on earth do they start morning sessions at 8am and require papers to be due before the conference? Why, damn it?! Maybe they're just guidelines and not actual requirements. Yeah, maybe that's it ...

Q & A

Sometimes, though not often, I actually talk about science. I have gotten excellent questions from readers, but I have generally answered them in the comment section. Since I figure most people aren't reading the comments, I thought I would consolidate some of the questions here. I am also preoccupied with editing chapter 4, so forgive a little re-hashing.

For a plasma wakefield refresher see acceleration basics, plasma wakefield basics and my thesis basics.

Q: Energy. Everyone keeps asking about energy. Basically, does this experiment obey the laws of physics and conserve energy? Provided we are not crackpot scientists and, in fact, conserve energy, how do we do that?

A: We are not crackpots. Odd, maybe, but not crackpots. Our experiment fully obeys the laws and regulations set forth in the universe. The system is a transformer. Yes, I say this every time, but, well, it's a damn transformer. The head particles lose energy such that the tail particles can gain energy. The way the energy is transferred is through the plasma wake. Some energy might be dissipated into the plasma, so it won't be a perfect 100% transfer, but you get the idea.

Q: At this point, people ask why the tail particles don't crash into the now less energetic head particles.

A: We are working with ultra-relativistic particles (28.5 GeV - if that means anything to you). Basically, the electrons in the bunch are going the speed of light. So when the head particle lose energy and tail particles gain energy, they are still basically going the speed of light. So there is no concern that the head particles will stop and tail particles crash into them.

Q: What is going on with the plasma ions and electrons?

A: The ions don't move on the time scale that the beam passes through the plasma, so they are not part of the wake. The wake is only composed of electrons from the ionized plasma. Having the ions stationary means they exert a nice focusing force on the electron bunch (also very good). The electrons in the wake all land behind the electron bunch, so there is a huge density spike on axis behind the bunch (sorry, that blue shaded region is supposed to be A LOT of plasma electrons, not ions, which I now realize it looks like). The density spike then administers the "kick in the ass".

Q: What is the maximum energy gain and what is the limit?

A: The maximum wave we can get is called the wave-breaking field. This maximum wave determines the energy *gradient* not gain. In other words, the limit on how large the plasma wake can get. The wave-breaking field is given by the following formula:

E_peak [V/m] = 96*sqrt(n_p[cm^-3])
where n_p is the density of the plasma. For a plasma with density 10^17 cm^-3, the maximum acceleration gradient is 30 GeV/m. The maximum amount of energy gained by the particles is then 30 GeV/m * (length of the plasma).

Q: Are you a proof-of-principle experiment?

A: Yes. We have gotten excellent results (hopefully to be published soon), so the experiment is progressing a little bit into more "are-you-practical?" type questions. This is still unclear, however, optimism remains high.

Q: What's your efficiency?

A: A good question, but one I hate. Mostly because we do not have a good answer. First and foremost, we are a proof-of-principle experiment, so proving good efficiency is a bit beyond our call at the moment. That's the cheap answer; the real answer is we basically don't know. We work with short bunches (~ 25 microns) and there doesn't exist a diagnostic which can time-resolve something that short. We know we lose a lot of energy in many particle and we know we gain a lot of energy in a few particles. We have a lower limit in knowing how many particles have gained energy, but we don't know the true amount. The not-knowing leaves us in a tough position to properly answer the efficiency question.

Q: Is it scalable for use on the International Linear Collider (ILC) if it is built with the cold design (superconductivity)?

A: I have no clue, but this question has been briefly looked at in advanced accelerator workshops. No solid results except that we have potential.

Q: Do any of your colleagues feel that the selection of the German approach (the cold design) was primarily a political decision, especially in light of the continuing quagmire over the ITER site?

A: Disclaimer: I do not work on the ILC, I have absolutely no knowledge about the inner workings on the technology decision for ILC, also I am not a particle physicist and I am in some weird branch of advanced accelerator physics, so I think we can all assume where my interests lie. With that large grain of salt in mind, I have had discussions with people on the subject. The most succinct commentary on the decision I heard: "They chose intensity over energy." As for the political ramifications of such a decision, I do not know. I do think that high energy physics community has realized that in order for the ILC to be built, the community needs to be supportive of any decision made. The moment there are internal fractures, it becomes too easy for the government not to support it financially. Whether they execute the cooperation fully will remain to be seen.

Okay, I think that is way too much science for one day. Any more questions, bring it on. I promise to answer them in time, which is heavily dependent on how much I want to avoid the responsibilities of the thesis writing.

Close Encounter

Generally I don't like (read: fear) animals unless they are domesticated. Although I enjoy seeing them in a zoo or observing them from my car, I would rather not have encounters without any sort of barrier between me and the animal. Part of this is due to my ignorance and part of it is due to past experience. This included a rather unfortunate incident with a goose. Thinking that geese must be nice, I learned a life lesson to the contrary and now believe all fowl must be evil incarnate.

With that background in mind, I went for a hike up at the Windy Hill Preserve. As I was turning around a bend, I came upon two wild turkeys. Since I am always thinking of my readers, I took out my camera and went in for a picture. Apparently I crossed some invisible boundary because one of the turkeys put his feathers up and started to come at me. This was definitely a gesture of great displeasure rather than greeting, so I did the only honorable thing – I darted back around the bend to hide. Since I was stuck on the trail until they moved on, I tried whistling loudly as a "shoo!" technique. In response to every one of my whistles, they gobbled replies back at me (perhaps they are not as wild as I thought). They were now camouflaged in the trees, but I was able to circumnavigate their location based on the direction of their gobbles. Thankfully, I made it past them without having another goose incident.

As I was unable to take pictures, here is my recreation of the scene (see the turkey and the chicken):

My Pyramid.

In the interest of avoiding my responsibilities, I have begun a downward spiral of wasting time. First, I mulled over the variety of photo options offered by both Shutterfly and Kodak Gallery (formally known as Ofoto). Shutterfly wins hands down, as I challenge you to figure out how to get a matte photo with white borders on Ofoto. Then I progressed to reading every frickin article on the New York Times website, which lead to a couple conclusions. First, I used to think David Brooks was a Republican I could tolerate, that no longer seems to be the case. And second, I have learned that I should be eating 7 ounces of grains, half of which should be whole.

The U.S. government just came out with a new and personalized food pyramid. After receiving my personalized pyramid, I was about to start bitching about portion size (find me a normal person who knows how many ounces constitute one slice of bread). Then I discovered that they anticipated such ignorance and even give pictures:

1 slice of Whole Wheat Bread == 1 ounce of whole grains.

But let it be known that 1 Kaiser Roll == 2.5 ounces of refined grains. (A kaiser roll is nicht so gut.)

Regardless, I think my consumption of diet coke, grilled cheese sandwiches and candy bars isn't really going to make the healthy list. And until the vending machine starts selling whole-wheat crackers and raisins, it's not looking like my diet is going to change any time soon. But that seems to be okay, because according to another NYT article, a little bit heft may be helpful.

Not So Bad.

All has been quiet because I have been working. Working a lot. I am trying to fix/improve/finish my Chapter 4 before my boss returns from the APS meeting in Florida. I have to say I am pretty proud of myself; I have cranked out 12 pages in about a week. I will not debate the quality of those 12 pages because, at this point, I more happy that I have some tangible measure of "progress" than actually producing good work.

I thought that, with a little more than a month, completing two chapters was going to be tough. It seemed like a normal reaction to me that I would be entering a stressful phase. I thought that way until dinner last night. Sam has been out of town for work for almost 3 weeks and just returned Monday night. To celebrate his return, we had dinner at his place with his roommates and some friends. One of the people at dinner is defending his thesis a week before I do. Excited to have found someone in a similar situation, I asked how the writing was going. His response: "I have an outline written for six chapters and one chapter kinda done."

I don't think I am feeling so bad now.

Caught.

I've been outed. I'm afraid I haven't been following the rules laid out by Peter in another QD blog entry. In particular I failed at rule #4, since I have never mentioned this blog to my boss nor to my coworkers. Why have I been so secretive? I genuinely thought QD was going to be completely unpopular and no one was going to read it. I mean, please, a blog about the lives of physicists?! So I thought I could keep the blog as more of a journal for myself, rather than have people actually read it. See ... no reason to share it, if nobody knows about it.

Then the Symmetry article came out. Granted the article is good publicity for our experiment, but it makes me cringe a little bit. Although it's good at explaining the physics, the language glosses over the group aspect of this experiment (which is a collaboration of SLAC, USC and UCLA). Instead there is language like "O'Connell envisions ..." O'Connell doesn't do s**t but take data and write a thesis to graduate. There are much more qualified individuals envisioning the future than me and, unfortunately, that isn't made very clear.

So some serious razzing has come my way as a result of this article, which caused an unnamed person's googling me and sharing it with a coworker, which finally concluded with that coworker outing me. This is not the scenario I wanted. Now I just hope I can avoid the "Chapter not ready, were you spending too much time blogging?" comments.

Clock Watching

This is what I have been doing every night for the last five nights. Staring at the clock. Praying for sleep to come but always alluding me. Instead of sleep, the moment my head hits the pillow, my mind has been swirling with all the things I need to do. First, I chronicle the tasks I want to accomplish, in decreasing order of importance. Then, I try to estimate how much time I need to finish each of the tasks and who I can harass to help me finish them faster. When I have exhausted the list, I then begin composing sentences. That's right, I start discussing physics with myself ... at two in the morning. How to best explain the field ionization of other gases being suitably vague so I don't have to do too much work, but still acceptable enough to relay the point, etc. etc. etc. Once I actually come up with a good sentence, I then agonize if I should get up and write them damn thing or stay in bed and hope I will fall asleep right now but still wake up tomorrow morning remembering my exact word choice.

Oh joy, only 52 more days of this.

Keep the Sunshine On

So this is the problem: America has an awful lot of people but we don't have enough energy resources to sustain this population growth without efforts at conservation. For some strange reason many Americans seem to be allergic to the word "conservation" as they often tend to associate it with "deprivation." True, we could legislate efficiency standards for home appliances, but that wouldn't be nearly as easy as drilling in Alaska.

However, it seems that someone actually came up with a clever plan. A plan that doesn't use those pesky words ("conservation" or "efficiency"), therefore, it actually has the potential to be passed. Granted, there are many other items on the table which might make it fail, but Congressman Upton (R-MI) added an amendment to the Energy Policy Act of 2005 which would extend Day Light Savings Time by two months. DST would start one month early in March and end one month later in November. The idea being people usually sleep in the early morning (myself included) rather than turning on lights and consuming electricity, whereas people tend to do those things after work when it is dark out. By extending sunlight until later, people's consumption of electricity when they get home would be reduced - indirectly helping conservation efforts. Honestly, I'm just in for the two extra months of sunlight after work. I could really dig that.